Simulation study of supercritical carbon dioxide jet fracturing for carbonate geothermal reservoir based on fluid-thermo-mechanical coupling model

Geothermal energy is a kind of renewable,sustainable and clean energy resource.Geothermal energy is abundant in carbonate reservoirs.However,low matrix permeability limits its exploitation.The super-critical carbon dioxide(SC-CO_(2))jet fracturing is expected to efficiently stimulate the carbonate geothermal reservoirs and achieve the storage of CO_(2) simultaneously.In this paper,we established a transient seepage and fluid-thermo-mechanical coupled model to analyze the impact performance of sc-CO_(2) jet fracturing.The mesh-based parallel code coupling interface was employed to couple the fluid and solid domains by exchanging the data through the mesh interface.The physical properties change of sC-CO_(2) with temperature were considered in the numerical model.Results showed that SC-CO_(2) jet frac-turing is superior to water-jet fracturing with respect to jetting velocity,particle trajectory and pene-trability.Besides,stress distribution on the carbonate rock showed that the tensile and shear failure would more easily occur by SC-CO_(2) jet than that by water jet.Moreover,pressure and temperature control the jet field and seepage field of sC-CO_(2) simultaneously.Increasing the jet temperature can effectively enhance the impingement effect and seepage process by decreasing the viscosity and density of SC-CO_(2).The key findings are expected to provide a theoretical basis and design reference for applying SC-CO_(2) jet fracturing in carbonate geothermal reservoirs.

Papillary cystadenoma of the parotid gland: A case report

BACKGROUND Papillary cystadenoma is a rare benign epithelial tumor of the salivary gland,which is characterized by papillary structures and oncocytic cells with rich eosinophilic cytoplasm. We found only one case of papillary cystadenoma in nearly 700 cases of salivary gland tumors. Our case was initially mistaken for a tumor of the right temporomandibular joint(TMJ) capsule rather than of parotid gland origin. Preoperative magnetic resonance imaging(MRI) and computed tomography(CT) should be carefully studied, which allows for appropriate preoperative counseling and operative planning.CASE SUMMARY Here, we report an unusual case of a 54-year-old woman with a parotid gland papillary cystadenoma(PGPC) that was misdiagnosed as a tumor of the right TMJ capsule. She was initially admitted to our hospital due to a mass anterior to her right ear inadvertently found 5 d ago. Preoperative CT and MRI revealed a well circumscribed tumor that was attached to the right TMJ capsule. The patient underwent a resection through an incision for TMJ, but evaluation of an intraoperative frozen section revealed a benign tumor of the parotid gland. Then we removed part of the parotid gland above the temporal facial trunk. The facial nerve was preserved. Postoperative histopathological findings revealed that the tumor was PGPC. No additional treatment was performed. There was no recurrence during a 20-mo follow-up period.CONCLUSION The integrity of the interstitial space around the condyle in MRI or CT should be carefully evaluated for parotid gland or TMJ tumors.

Seroepidemiology of Syphilis Infection among 2 Million Reproductive-age Women in Rural China：A Population-based, Cross-sectional Study

Background：Quantifying syphilis prevalence is important for planning interventions and advocating for resources on syphilis.However,data on large sample studies regarding the prevalence of syphilis among reproductive-age women in rural China were not available for analysis.The aim of the study was to determine the prevalence,epidemiological characteristics,and related factors of syphilis infection among reproductive-age women in rural China.Methods：Data were obtained from a nationwide,population-based,cross-sectional study under the National Free Preconception Health Examination Project which covered all the 31 provinces in China's Mainland.Women intending to get pregnant within the next 6 months were enrolled between January 1,2010,and December 31,2012.Sociodemographic,gynecological and obstetric characteristics,and other relevant information were obtained through face-to-face interviews.Treponema pallidum particle agglutination assay test was used to detect positive samples of syphilis.Univariate and multivariate logistic regressions were performed to assess the associations between syphilis seropositivity and related factors.Results：The overall seroprevalence of syphilis （SPS） among the 2,044,126 women who received syphilis screening test during 2010-2012 was 0.37% （95% confidence interval [CI]：0.36-0.37%）.The SPS appeared 0.24% （95% CI：0.23-0.26%） and 0.66% （95% CI：0.59-0.72%） in women at 21-24 and 40-44 years of age,respectively,showing an increase of SPS,parallel with age,and the difference was significant.SPS was significantly higher in ethnic minorities than that in Han nationality （0.58% vs.0.35%,respectively,odds ratio [OR] =1.41,95% CI：1.30-1.53） and higher in workers than that in farmers （0.45% vs.0.36%,respectively,OR =1.27,95% CI：1.14-1.41）.Women with primary school or below level had a higher SPS as compared to those with college or above educational level （0.61% vs.0.32%,respectively,OR =2.49,95% CI：2.14-2.89）,and the increase reversely correlated with the levels of education.Women whose spouses were syphilis seropositive had significant greater risk （OR =48.26,95% CI：44.38-52.48） as compared those whose spouses were seronegative.Women who reported having had a history of sexually transmitted infections were more likely to be tested positive for serological syphilis （OR =27.17,95% CI：20.44-36.11） as compared to those without.Conclusions：High SPS is seen among reproductive-age women in rural China that calls for targeted interventions on syphilis prevention and control in this target population,with emphasis on those who are 35 years of age and above,less educated,being minor ethnicity,workers,and living in the western regions of China.